Senior Full Stack Software Engineer (various levels) - Production Team

Ljubljana, Slovenia | Product Development | Full-time | Fully remote



About Celtra

At Celtra, we are building two world-class products. The first product (Creative Enablement or CE) has already been a growing market leader for a couple of years now, helping companies such as CNN, TripAdvisor, Bloomberg, NBCU, and Business Insider monetize their advertising inventory. It covers the entire lifecycle of launching a campaign: ad product ideation and design, ad content production, trafficking tags, and tracking performance. With our second, younger product (Creative Automation or CA), we are chasing a much bigger opportunity by helping brands produce a massive amount of content better, faster, and more efficiently. Although its development is still in the early days, it already includes an impressive list of customers such as Spotify, adidas, Shopify, Unilever, P&G, LEGO, Lululemon, and many others. 


What is our team responsible for? 

The Production team is responsible for our industry-leading web-based WYSIWYG editor, loved by  thousands of designers who use it daily to build image, video, and social ads.

Unlike tools like Photoshop which require you to build one asset at a time, global advertisers like Adidas, Spotify, and Unilever use Celtra to automatically generate tens of thousands of ad variations for different languages, countries, products and platforms.


Who are we searching for? 

We are looking for Fullstack and Frontend software engineers with appreciation for Frontend technologies to join the journey of building Creative Automation team (CA). We are looking for a motivated, constantly-learning engineer who understands how browsers and their APIs work. 


In the past we built

  • We have built an industry-leading web-based WYSIWYG editor that allows designers to produce Creative templates with a great variety of design elements, smooth animations, video editing timelines and smart image functionalities.
    Together with our specialised spreadsheet-like content editor, marketers and designers are able to scale these templates into thousands of ads variations, faster and easier than ever before.
  • Our Photoshop plugin brings existing design tools closer to Celtra.
  • For our content scaling to work, we implemented video transcoding and transforming services for cross-platform and cross-product support. 
  • Along the way, we also created our own DesignSystem UI components library, for developers to use.


What are the challenges ahead?

We believe that software should be easy to use and enable users to collaborate efficiently. We want to bring multiplayer functionality in our Authoring tools, allowing editors collaborating on design and content simultaneous. For that, we'll need to rework our current architecture, along with introducing a novel concept of an integrated WYSIWYG editor with multiple content spreadsheets.


To bridge the gap between existing design tools and our content scaling solution, we will invest our effort in Figma & Photoshop integrations, while also providing our users with time-saving features like AI-based automatic focus and cropping service. Additionally, we are also planning to release the next generation of our headless Chromium-based rendering pipeline.


What kind of tech stack do we use?

Our CA product is using NodeJs, PHP, MySQL, Redis and Python. For both products, on the front-end, we use Vue.js, NPM, Webpack and vanilla JavaScript when needed. Everything runs on the AWS cloud, and the Kubernetes cluster orchestrates it.


What are our expectations?

You care about clean code. You write high-quality, maintainable code and are aware of industry best practices and trends. You proactively identify possible technical issues  before it turns into long-term problems,  and you encourage others to do the same. We always do code reviews to provide feedback and ensure code quality.


You have a product mindset. We are not a feature factory. We have cross-functional teams with engineers, product managers, and product designers who are crafting a solution for a problem since day one. There is a lot of fun in this phase, requiring a lot of ingenuity, hacking, and validating.


You have strong troubleshooting skills. You are not afraid to parse logs, look at machine metrics or go deep into the code to understand what went wrong. You do not jump to conclusions, but act based on facts and evidence. 


You’re a team player. You work well in the team, are willing to share the knowledge, and want to help others as you know only a strong team can succeed.


What would be your responsibilities? 

  • Create performant interfaces that are a joy to use
  • Contribute to technical direction of our modules, define them and execute on them
  • Help define and improve the architecture
  • Code, review other people's code, ensure code quality, be a good boy scout, etc..
  • Work with the Products, Customer support and other internal teams to solve challenges
  • Teach and help junior/mid-level developers grow
  • Help plan and transfer old parts of the codebase to state of the art



  • 3+ years of experience in programming and following modern software development processes. 
  • Have experience of building single-page applications using modern web technologies (Javascript / TypeScript / CSS / HTML) and frameworks (VueJS / React / Angular).
  • Have experience with server-side principles (scaling, concurrency, etc. and back-end technologies (PHP, Python, Golang, Ruby, etc.).
  • Have understanding and experience of relational databases (e.g., MySQL) or document databases (e.g., Mongo).
  • Have experience with writing a unit, integration, and end-to-end tests. 
  • Willingness to learn, sharing our passion for constant improvement 
  • Experience with complex business software and large codebases
  • Experience with developing and deploying performant frontend code
  • Show passion for learning, and help us learn too.
  • Be fluent in written and spoken English.


We appreciate:

  • Experience with TDD & CI 
  • A big plus is some interest in or experience with UX/UI
  • Understanding of various software paradigms and architecture styles (REST, OOP, functional programming, state management, etc.)
  • B.Sc. or higher in Computer Science or a related field  
  • Be open to collaborate in the tech community 


What do we offer? 

In Celtra it’s all about looking beyond the surface, beyond the numbers, and really trying to see the qualities that are at the core of each person, their talents; the discovered ones or better still, the undiscovered ones. We look for people who naturally want to take responsibility for their own success, and strive to do something that has a tangible impact. 

To our best talent, we give them the freedom to do the unusual. 


Compensation depends on experience and knowledge, but here’s what we offer in general:

  • A competitive benefits and compensation package 
  • We place great importance on the professional development of our employees 
  • Comprehensive health coverage and additional pension insurance 
  • We provide plenty of opportunities for employees to seek a more active and healthy lifestyle. We provide a dedicated budget for any kind of sport activities employees are passionate about, and we sponsor group sports activities such as basketball and yoga lessons. 
  • We provide employees with top-notch working equipment and an additional budget for your home office.